1. Field of the Invention
This invention relates to an image forming apparatus such as a copying device or a printer which is provided normally with a standard feeding unit and optionally with an optional feeding unit.
2. Description of the Prior Art
The image forming apparatus such as the copying device or the printer is provided with a paper feeding unit which holds recording papers. These recording papers are carried one at a time from the paper feeding unit to the image forming system, in which a toner image is transferred onto the recording paper and fixed thereon. Image forming apparatuses of some types are adapted to be provided with a plurality of paper feeding units. An optional feeding unit is disposed below the standard feeding unit as connected thereto (refer to Japanese Laid-Open Patent Application 03-115,026).
The optional feeding unit is provided as with a paper feed roller adapted to discharge the recording papers stored in the unit one by one. The drive force for rotating this paper feed roller and discharging and forwarding the recording papers is transmitted from a motor which is disposed in the main body of the image forming apparatus. The standard feeding unit, therefore, is provided with a drive force transmission system which transmits the drive force mentioned above to the optional feeding unit disposed thereunder. This drive transmission system includes a gear system and the like.
Such electric signals as a signal indicating the detection of presence or absence of paper supply and a signal for starting paper feed which are to be used in the optional feeding unit are also transmitted from the main body of the image forming apparatus. The standard feeding unit, for the purpose of transmitting the electric signals mentioned above to the optional feeding unit disposed thereunder, is provided with an electrical connector which is capable of being connected to an electrical connector installed in the optional feeding unit. The electrical connector includes a freely detachable connector and the like.
In the image forming apparatus of the type having the optional feeding unit connected to the lower part of the standard feeding unit, a part of the gear system or the connector of the drive transmission system installed in the standard feeding unit is fated to be exposed under the standard feeding unit to the exterior.
When the part (gear or connector) connected to the optional feeding unit is exposed to the exterior, however, it calls for careful handling and possibly causes trouble. Logically, an idea of solving this problem by concealing the exposed part with a lid or a cover may be conceived. When the cover is actually adopted, a user is compelled to take the trouble of removing this cover whenever he attaches the optional feeding unit to the image forming apparatus. Further, the cover constitutes an addition to the component parts of the apparatus and entails an increase in cost of production of the apparatus.